This invention relates to a resonant method and a resonant apparatus comprised of a wall body or bodies which reduce a sound's pressure within a whole sound field, which field has a certain extent. The invention provides wall surfaces of prescribed construction as a resonant wall body or bodies at the side of a sound's source. The invention especially relates to a method and an apparatus of decreasing sound's energy comprising wall surfaces which enable remarkably reduced sound pressure in a whole sound field at the side of a sound's source. The apparatus comprises: a porous outside cover coat-laminated to the external edges of the body ribs. The bodies may be made of heavy materials such as metals and concrete etc. The ribs are set at given intervals to the vertical or to the horizontal or to both directions. The resonant wall body or bodies is formed by isolating open edges of the airlayer with rigid materials and forming wall surfaces so as to screen a sound's source using said resonant wall body or bodies. The sound from said sound's source is resonated in a whole space composed of said resonant wall body or bodies as well as the enclosed volume of the body or bodies.
Known resonant walls have rib materials comprised of materials such as Copenhagen rib etc. and are used as a finishing material of a wall for special buildings such as concert halls, public halls, or the like. This known type of resonant wall, however, has a simple construction with many ribs on the surface of the wall. The object of such walls is only to give an absorptive action of sound on the wall so as to make the sound's pressure within the enclosure constant without changing the tone quality. The walls are not intended for remarkably reducing the sound's energy from a sound's source in the whole space.
Furthermore, the soundproof wall used to conform to public nuisance requirements cannot reduce a sound's pressure in an entire sound field at the side of sound's source because such walls generally diminish the sound as a function of the sound's distance notwithstanding the existence of the sound absorptive properties of the material.